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51 Cards in this Set
- Front
- Back
the 6 nuclei located dorsally in the caudal medulla are __
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nucleus gracilis
nucleus cuneatus nucleus of the spinal tract of V |
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where is the corticospinal tract located in the caudal medulla?
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in the pyramids!
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what is the difference b/t the dorsal column and medial lemniscus?
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the fasciculus gracilis and the fasciculus cuneatus synapse in the caudal medulla on their nuclei. the 2nd order fibers then loop around and cross to run in the medial lemniscus. the man is on the pyramid, meaning the "leg" dorsal column fibers start medially and wind up more ventrally in the medial lemniscus, and the the "arm" dorsal column fibers start more laterally and wind up dorsally in the medial lemniscus
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what man is standing on the pyramid?
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the medial lemniscus
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why does a stroke in which the lateral and ventral corticospinal tracts are lost on one side spare the axial musculature?
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the ventral corticospinal tract projects bilaterally to the axial musculature
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what are the modalities of the dorsal column?
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vibration and proprioception
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what are the modalities of the spinothalamic tract?
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pain and temperature
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what are the dorsal column nuclei?
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nucleus gracilus and cuneatus
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where do the dorsal column fibers first synapse?
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at their nuclei in the caudal medulla
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what are arcuate fibers?
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arcuate fibers are fibers running from the dorsal column nuclei to the medial lemniscus on the other side. they make a loop, and they are visible
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where are the fasciculus cuneatus and gracilus found in relation to their nuclei
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the fasciculus gracilus and cuneatus are found lateral to their nuclei. the spinal tract of V is also found lateral to its nucleus in the caudal medulla
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where is the spinal tract of V located?
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from the pons to C2
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what puts the head on the homunculus of the spinothalamic tract?
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the spinal tract of V
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where are the cell bodies of the spinal tract of V neurons located?
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in dorsal root ganglia
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what nucleus is replaced by the dorsal horn?
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spinal tract of V
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what does damage to the spinal tract of V in the medulla cause?
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same sided sensory deficits (it hasn't crossed yet)
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what kind of sensory deficits would a lesion of the spinothalamic tract and the spinal tract of V in the medulla cause?
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same sided facial pain and temp sensory deficits. contralateral sided pain and temp deficits on the rest of the body
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what are the 4 nuclei associated w/ CN V and their modalities?
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motor nucleus of V - muscles of mastication
spinal nucleus of V - pain and temperature mesencephalic nucleus main sensory nucleus |
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where do spinothalamic tract fibers first synapse?
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the dorsal horn
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trace the path of spinothalamic fibers from origin to the thalamus
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come into the dorsal horn
synapse and cross over via the anterior white commissure leg fibers come into tract first and are located laterally; head fibers are located medially and ascend in the spinothalamic tract. they eventually run into the VPM and VPL nucleus in the thalamus. VPM - head and VPL - legs |
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what tract does syrinx screw up?
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spinothalamic tract (anterior white commissure)
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at what level does the spinothalamic homunculus get a head?
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the notes say mid pons....
gradually throughout the medulla and pons as the fibers from the spinal tract of V cross over (no arcuate like the dorsal column) |
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what is lissauer's tract
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located dorsal and lateral to the dorsal horn, it is a white matter tract that allows spinothalamic tract fibers to ascend or descend a few segments before they synapse in the dorsal horn. this is why when you use a pin, you can be off by a level or 2
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where do hypoglossal nerve roots exit?
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b/t the olive and the pyramid
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what is the differece in the location of the hypoglossal nucleus in the caudal and rostral pons?
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the hypoglossal nucleus floats to the top in the rostral pons?
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what is the dead giveaway for the rostral pons?
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the inferior olivary nucleus
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what fibers go into and come out of the inferior olivary nucleus
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central tegmental tract fibers enter the inferior olivary nucleus and olivocerebellar fibers leave the ION, cross, and go into the inferior cerebellar peduncles
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what is the nebulous region medial to the solitary nucleus, and what does it do?
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this is the reticular formation. here are the neurons that control HR, BP, and symp pathways. they are spread out so a small stroke/lacune/lesion wont kill you!
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what is the function of the solitary nucleus?
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the solitary nucleus is a special sensory nucleus that is connected to sensory neurons that sample blood for toxins, CO2 and pressure. these come from the glossopharyngeal and vagus
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what is dysautonomia
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when the nerves that synapse on the solitary nucleus do not function correctly, and the reflexes that govern BP, etc dont work right! wildly fluctuating BP's
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what is cervical dystonia
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problem w/ CN XI, trapezius and SCM contract on one side resulting in your head being stuck on one side
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where do solitary nucleus fibers synapse for reflexes?
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the dorsal motor nucleus of X, which goes to blood vessel smooth muscle and cardiac muscle. when you stand up, it increases vascular tone so you dont faint.
dorsal motor nucleus of X also controls gut motility |
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what controls gut motility?
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dorsal motor nucleus of X
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what does the dorsal motor nucleus of X do?
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it innervates vascular smooth muscle and cardiac muscle. involved in reflexes. also influences autonomic functions such as gut motility.
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what does CN V Do?
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sensory to the face and motor to Muscles of Mastication.
(headaches too!) |
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what level of the brainstem does CN XII indicate?
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medulla
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what level of the brainstem does CN V indicate
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mid pons
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what motor nucleus controls the skeletal muscle in the larynx, the pharynx, and palate?
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Nucleus Ambiguus
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____ contains special visceral fibers which contribute parts to CN IX, X and XI
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nucleus ambiguus
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only muscle innervated by CN IX
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stylopharyngeus
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which cranial nerve's fibers go into NTS
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IX
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CN that is most difficult to test with a neurological exam
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XI - taste and stylopharungeus
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a nucleus made up of primary sensory pseudounipolar neurons that were sucked into the brainstem
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the mesencephalic nucleus of V
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how does the jaw-jerk reflex occur?
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sensory neurons go into the mesencephalic nucleus of V and synapse directly on the motor nucleus of CN V, which controls the muscles of mastication
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where are the vestibular nuclei located in the rostral medulla
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at the top, laterally.
medial to the interior cerebellar peduncles dorsally to the solitary nuclues and tract |
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what do the vestibular nuclei do?
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the send information from the inner ear to the "eyes and axial musculature"
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where do fibers from the vestibular nucleus go?
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some go to the ventral funiculus of the spinal cord to the axial musculature to tell these muscles about your position in space
some go through the medial longitudinal fasciculus to talk to the nuclei which control eye movements |
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why do they test the horizontal conjugate gaze in a sobriety test?
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the medial longitudinal fasciculus is especially sensitive to EtOH. it is needed for the vestibular nucleus to tell the nuclei that control eye muscles where the eyes are looking.
when III and VI cant work together you get nystagmus (rapid flipping back and forth) |
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what is the area postrema
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the lining of the 4th ventricle, aka the vomiting center, which tastes the CSF for toxins
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where is the dorsal column tract located in the rostral medulla
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it is now the medial lemniscus and is standing on the pyramid
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where is the medial longitudinal fasciculus located?
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in the middle, kinda dorsally, ventral to the hypoglossal nucleus
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